package com.tledu.mr;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import java.io.IOException;
import java.util.StringTokenizer;

public class WordCountDriver2 {
    public static class WordCountMapper1 extends Mapper<Object, Text, Text, IntWritable> {
        private IntWritable one = new IntWritable(1);
        private Text word = new Text();

        @Override
        protected void map(Object key, Text value, Context context) throws IOException, InterruptedException {
            StringTokenizer str = new StringTokenizer(value.toString());
            while (str.hasMoreTokens()) {
                word.set(str.nextToken());
                context.write(word, one);
            }
        }
    }


    public static class WordCountReducer1 extends Reducer<Text, IntWritable, Text, IntWritable> {
        private IntWritable freq = new IntWritable();

        @Override
        protected void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {
            int sum = 0;
            for (IntWritable val : values) {
                sum += val.get();
            }
            freq.set(sum);
            context.write(key, freq);
        }
    }


    public static void main(String[] args) throws IOException, InterruptedException, ClassNotFoundException {
        Configuration conf = new Configuration();
        Job job = Job.getInstance(conf, "kxr");

        job.setJarByClass(WordCountDriver2.class);

        job.setMapperClass(WordCountMapper1.class);
        job.setCombinerClass(WordCountReducer1.class);
        job.setReducerClass(WordCountReducer1.class);

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);

        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}
